ADDIS ABABA (Reuters) - The International Criminal Court has shown "double standards" by pursuing only Africans so far and should defer trials of Kenya's leaders or take other steps so they can fulfil their elected offices, Ethiopia's prime minister said on Thursday.

Hailemariam Desalegn was speaking before an African Union summit in Addis Ababa that will discuss relations with the court which has convicted only one man, an African warlord. The only others charged are also Africans.

In an interview with Reuters, Hailemariam also said al Shabaab militants in neighbouring Somalia were weakened despite their attack on a Kenyan shopping mall last month, but Western states and others needed to do more to crush the Islamist group.

Ethiopia, which hosts the African Union headquarters, also currently chairs the 54-nation body. Of its members, 34 states have signed the statute that set up the war crimes court in The Hague, which has drawn increasingly strong African criticism.

Hailemariam said the ICC was effective in pursuing the weak, but not the powerful. "The bigger you are and powerful you are this instrument does not work but the weaker you are and the instrument works. So that double standard has to be avoided," he said, referring to the court's failure to act beyond Africa.

Kenyan President Uhuru Kenyatta's trial, which starts in November, is the first by the court of a sitting president, while that of his deputy, William Ruto, began last month. They are accused of orchestrating bloodshed after a disputed 2007 election, charges they both deny.

Hailemariam, whose country is not a signatory to the ICC, said the court had rejected a request to defer the cases. He said Kenyans had elected Ruto and Kenyatta so it should ensure they can conduct their political duties. "We are not objecting to the court, we are objecting to the way it acts," he said.

An AU official had previously said Saturday's summit would discuss a mass walkout by the African signatories to the court statute, a position he said Kenya was lobbying for.

"DESPERATE ACTION"

But in comments that appeared to indicate limited support for such action, Kenyan Foreign Minister Amina Mohamed said the summit would discuss "relations" with court and denied that Nairobi had ever sought a mass withdrawal.

Kenya is still reeling from the attack on the Westgate mall in Nairobi in which 67 people were killed. Al Shabaab claimed responsibility, saying it was demanding that Kenyan troops withdraw from Somalia where they have battled the group.

Hailemariam, who like Kenyan leaders has sent troops to Somalia, said the mall attack was a "desperate action" by a group "at its weakest in history".

That view is echoed by analysts, who say the raid may have been an attempt to drum up support when the group has lost ground at the hands of African troops. But they also say al Shabaab may have greater capacity to strike abroad.

"You don't need to have more forces (in Somalia) to fight al Shabaab at this time," Hailemariam said, when asked if he would boost the Ethiopian presence there. "The only thing we need is support for the Somali security forces to be strong."

This, he said, required a more concerted effort from the United States and European countries with the capacity to offer such help, as well as from Asian nations, such as China.

"I think if we strengthen the Somali security forces - with the support of (African peacekeepers) AMISOM and Ethiopian forces - I think it is possible to defeat al Shabaab. It is not something which is so complex," he said.

Although his country shares a border with Somalia, Hailemariam said militant ideas could be curbed provided the Ethiopian "people are conscious enough to fight this extremism and terrorism".

Ethiopia has a Christian majority but about a third of its population is Muslim. Some Muslims have complained the government has interfered with religious affairs as it tries to stop what officials say is a rise in Islamist ideology.

Hailemariam dismissed the criticism. "The government has nothing to do with religion," he said. "The only thing we say is there is a red line for any religion in the country which goes beyond the constitutional provision."